She says the indictment against Williams alleges he used his position as a professor of gender and sexuality studies to travel internationally and prey on underage boys.

The U.S. Department of Justice says Williams traveled to the Philippines in January 2011 to engage in sex acts with two 14-year-old boys he met online in 2010. He fled the Los Angeles area approximately one week after returning from the Philippines.

The FBI offered a reward of $100,000 for information on Williams' whereabouts when they placed him on their most wanted list on Monday. He was captured Tuesday drinking coffee near a park in the Caribbean beach town, according to The Associated Press.

"I analyzed the computers and the camera that belong to Williams and found child pornography," Jeff Yesensky, FBI special agent, said in a video posted online Monday to bring awareness to the case.

"Because of his status, he has the means and access to children, and that's what makes him dangerous," Yesensky said. "He preys on the most vulnerable children."

Mexican authorities said it was unclear how long Williams had been in Playa del Carmen. They also didn't say whether he is suspected of committing any crimes in Mexico.